Principal Architect in London

We re looking for a seasoned Architecture Lead to own and drive KAST s technical strategy as we scale our global fintech platform.

You will be the primary technical authority for our system design, responsible for ensuring that our high-throughput transaction engines and complex microservices ecosystem remain resilient, performant, and secure under massive load.

You will partner with Engineering, Product, and Security leadership to bridge the gap between business growth and technical execution, setting the standards for how we build, deploy, and evolve our transactional infrastructure on AWS.

Department Engineering. Employment Type: Full Time. Location: London. Workplace type: Hybrid.

• What You ll Be Doing
• Own the
• Architectural

Vision: Define and drive the long-term technical architecture for KAST, ensuring our platform evolves to meet the demands of high-throughput transactional volume.

• Design for Scale & Reliability: Lead the design and review of our distributed systems, ensuring our microservices architecture is built for fault tolerance, high availability, and massive scalability on AWS.
• Optimize
• Transactional

Flows: architect critical path systems, including our payment processing, ledger management, and financial data consistency models, ensuring sub-millisecond performance and auditability.

• Establish
• Engineering

Standards: Define architecture principles, coding standards, and deployment patterns (CI/CD, Ia C) that enable autonomous microservices teams to ship code safely and rapidly.

• Cloud-Native Strategy: Lead our AWS strategy, optimizing resource utilization, latency, and cost while leveraging managed services to improve developer velocity.
• Drive Security & Compliance: Integrate security-by-design principles into our architecture, ensuring that our transaction-heavy environment meets strict financial compliance standards (PCI-DSS, SOC2).
• Influence & Mentor: Act as a force multiplier for the engineering organization by mentoring senior engineers, leading architecture review boards, and guiding major technical decisions.
• What You ll Bring
• Proven
• Fintech

Leadership: 10+ years of software engineering experience, with a significant track record architecting large-scale payment platforms, ledger systems, or high-volume financial infrastructure.

• Distributed
• Systems

Expert: Deep expertise in microservices architecture, event-driven design, and the trade-offs inherent in building consistent, high-throughput distributed systems.

• Cloud-Native Proficiency: Extensive experience designing and operating complex, high-traffic applications on AWS.
• Data & Transaction

Integrity: Strong understanding of database patterns for financial data, including transaction atomicity, consistency models, and handling distributed data across microservices.

• Strategic

Influencer: Demonstrated ability to influence technical direction across multiple teams, manage stakeholder expectations, and drive consensus on complex architectural trade-offs.

• Security & Compliance

Awareness: Knowledge of designing for security within a regulated industry, understanding how to protect sensitive financial data while maintaining system throughput.

• Growth Mindset: Ability to balance immediate delivery needs with long-term architectural debt management.
• About KAST

KAST is redefining stablecoin banking for global citizens, crypto professionals, Web3-native businesses, and high-inflation markets hungry for USD-backed banking.

Backed by top-tier global investors and led by the ex-APAC CEO of Circle, our leadership team spans Circle, Airwallex, Revolut, Wise, Grab, Zoom, AWS, and leading OTC desks.

We ve scaled from zero to nearly a million users at ridiculous speed.

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